The present invention relates to a digital broadcasting receiving apparatus and a control method thereof for receiving, say, digital television broadcasts. More particularly, the present invention relates to a digital broadcasting reception technology using a time-shift feature of a data storage apparatus.
First, the following describes a reception signal supplied to the digital broadcasting receiving apparatus. In the following description, broadcasting information signifies information acquired by combining a plurality of information sources for providing digital broadcasting services.
Content information is a generic term for indicating contents of video information, voice information, and other programs. For example, the content information constituting contents of an ordinary television broadcasting service comprises video information and voice information. The content information constituting contents of an ordinary radio broadcasting service comprises just voice information.
Information for controlling reception operations of the digital broadcasting receiving apparatus is referred to as reception control information. The broadcasting information includes one or more content information and reception control information entities.
A transmission signal is a radio wave or a wired signal converted and modulated so that broadcasting information can be transmitted via a specified transmission path. In broadcasting signals, the transmission signal is transmitted via the transmission path and is then converted to an electric signal. This electric signal is used as a reception signal.
Presently, many commercialized digital broadcasting systems use broadcasting information by multiplexing various types of information in a stream format. This stream format is known as the MPEG (Moving Picture Image Coding Experts Group) 2 transport stream (hereafter referred to as MPEG2-TS) specified by ISO (International Organization for Standardization)/IEC (International Electrotechnical Commission)-13818-1.
As specified in ARIB (Association of Radio Industries and Businesses)-STD-B10, ARIB-STD-B24, ARIB-STD-B25, and the like published from Association of Radio Industries and Businesses, for example, there are extended formats of information multiplexed in compliance with MPEG2-TS.
The following describes an example which uses the MPEG2-TS as broadcasting information. As the content information, the broadcasting information contains one or more of content information types such as for video services, voice services, and other data broadcasting services. The PSI (Program Specific Information) is contained as the reception control information.
As described in ARIB-STD-B10, the PSI information contains PMT (Program Map Table) information and PAT (Program Association Table) information and the like. The PMT information indicates how the video information, voice information, or data information is transmitted in a received stream. The PAT information provides how the PMT is multiplexed.
There are provided various extended formats for signals multiplexed with MPEG2-TS. For example, as described in ARIB-STD-B10, it is possible to include SI (Service Information). Further, as described in ARIB-STD-B25, it is possible to include ECM (Entitlement Control Message) for controlling reception of the conditional access broadcasting and mail information such as announcement from a broadcasting station.
As described in ARIB-STD-B24, the same broadcasting information can be used to transmit the content information for sending and receiving data broadcasts (hereafter referred to as the data broadcasting content information). The data broadcasting content information can be used to reference the content information in video and voice information, making it possible to provide the data broadcasting content in the form of multimedia services including these video and voice services.
The digital broadcasting receiving apparatus receives a transmitted reception signal and generates a display signal for providing an indication corresponding to the content. The display signal is processed in a display apparatus and is supplied to users as video or voice data.
With respect to data broadcasting, it is possible to provide a program by combining video, voice, and data. For example, in the middle of a video or voice program, a news flash can be broadcast with multiplexing in the form of data broadcasting information and superimposed on video or voice. It is also possible to display news in a blank area prepared by reducing a video image area.
The data broadcasting may provide a data broadcasting service by concurrently displaying an ordinary television broadcasting service.
When the main program content is provided along with video and voice, additional information in the data broadcasting may not only be useful, but also unnecessary or nonurgent depending on users or cases. When such additional information is unnecessary or nonurgent, losing part of the image or reducing the screen for unnecessary information is merely degradation of the content quality to the users.
The above-mentioned conditional access broadcasting provides a PPV (Pay Per View) program which requires charging for individual programs. Basically, such a program is available only when the user subscribes to it. Before a possible subscription, a preview period is provided for the user to determine the subscription. During this preview period, descrambling can be activated. The display of the content information is accompanied by an indication notifying the preview in progress for promoting the subscription.
When the preview period expires without subscription to the program, the content information cannot be descrambled, preventing the program from being enjoyed. However, even after expiration of the preview period, it is possible to subscribe to that program under a specified condition. Subscribing to the program enables to audiovisually view the content.
As mentioned above, since an indication showing that the preview is in progress is displayed during the preview period, a part of the screen is obstructed, which can annoy the user. After expiration of the preview period, a blackout occurs until the subscription is completed. Thus, even if a user subscribes to the program, he or she cannot audiovisually view the content during a period between the blackout and the completion of the subscription. Either case results in worsening the quality of program service for users.
As mentioned above, when an interrupt factor occurs in the active program, the conventional digital broadcasting receiving apparatus displays associated information concurrently with the broadcast content. To users, this may be a loss of the quality in the original content.
For example, a PPV program is unviewable until a specified process is executed for subscription. Even if a viewing restriction condition is cleared to make the program viewable, the conventional digital broadcasting receiving apparatus makes it impossible to view the content already broadcast before the subscription.
Theoretically, a user can view the content by explicitly starting recording in a storage apparatus before the program becomes unviewable according to the viewing restriction. However, whether the content is stored appropriately largely depends on how the user utilizes the apparatus. Further, the user is necessitated to do complicated operations.